From: "gordon jacobson"
Date: 16-Mar-93 00:46:12
Subj: into the fibersphere
Newsgroups: alt.dcom.telecom
Organization: Channel 1 Communications
I have seen references to the following article in this and other
newsgroups. I contacted the author and Forbes and as the preface
below indicates obtained permission to post on the Internet. Please
note that the preface must be included when cross posting this article
to another newsgroup.
The following was received directly from George Gilder on Saturday March 6.
-----------------
Date: Sat Mar 06, 1993 2:58 pm GMT
From: George Gilder / MCI ID: 409-1174
TO: Gordon Jacobson
Subject: PLEASE UPLOAD TO INTERNET
The following article, INTO THE FIBERSPHERE, was first published in
slightly different and shorter form in Forbes ASAP, December 7, 1993. It
is a portion of my book, Telecosm, which will be published next year by
Simon & Schuster, as a sequel to Microcosm, published in 1989 and Life
After Television published by Norton in 1992. Subsequent chapters of
Telecosm will be serialized in Forbes ASAP beginning with the March issue
containing a theory of wireless communications.
PLEASE POST "FIBERSPHERE" TO ANY USENET
NEWSGROUPS THAT MAY BE DEEMED SUITABLE.
THE COMING OF THE FIBERSPHERE
In a world of dumb terminals and telephones,
networks had to be smart. But in a world of
smart terminals, networks have to be dumb.
BY
GEORGE GILDER
Philip Hope, divisional vice president for engineering systems of EDS,
has an IQ problem. His chief client and owner, General Motors, wants to
interconnect thousands of 3-D graphics and computer aided engineering (CAE)
workstations with mainframes and supercomputers at Headquarters, with
automated assembly equipment at factories in Lordstown, Indiana, and
Detroit, with other powerful processors at their technical center in
Warren, Michigan, with their Opel plant in Ruesselheim, Germany, and with
their design center outside San Diego. On behalf of another client, Hope
wants to link multimedia stations for remote diagnostics, X-ray analysis,
and pharmaceutical modeling in hospitals and universities across the
country.
Any function involving 3-D graphics, CAE, supercomputer visualization,
lossless diagnostic imaging, and advanced medical simulations demands large
bandwidth or communications power. Graphics workstations often operate
screens with a million picture elements (pixels), and use progressive
scanning at 60 frames or images a second. Each pixel may entail 24 bits of
color. That adds up fast to billions of bits (gigabits) a second. And
that's for last year's technology in a computer industry that is doubling
its powers and cost effectiveness every year.
What Hope needs is bandwidth and connections. The leading bandwidth
and connections people have always been the telephone companies. But when
Hope goes to the telephone companies, they want to tell him about
intelligence: their Advanced Intelligent Network which will be coming on
line over the next decade or so and will solve all his problems. For now,
they have what they call DS-3 services available in many areas, operating
T-3 lines at 45 megabits (million bits) a second. These facilities are
ample for most computer uses and working together with several different
Regional Bell Operating Companies (RBOCs), Hope should be able to acquire
these services in time for a General Motors takeover by Toyota.
Hope has been through this before. In the early 1980s, he actually
wanted D-3 services. Then he was interconnecting facilities in Southeast,
Michigan, with plants in Indiana and Ohio. But Michigan Bell could not
supply the lines in time. EDS had to build a network of microwave towers
to bear the 45 megabit traffic. Later in the decade, the phone companies
have even offered him higher capacity fiber optic lines, with the
requirement that the optical bits be slowed down and run periodically
through an electronic interface so the telco could count the number of
"equivalent channels" being used.
What Hope and others in the systems integration business need is not
intelligent networks tomorrow but dumb bandwidth that they can deliver to
their customers flexibly, cheaply, and now. To prepare for future demand,
they want the network to use fiber optics. It so happens that America's
telephone companies have some two million miles of mostly unused fiber
lines in the ground today, kept as redundant capacity for future needs.
Hope would like to be able to tap into this "dark fiber" for his own
customers.
As a leader in the rapidly expanding field of computer services, EDS
epitomizes the needs of an information economy. With a backlog of 22
billion dollars in already contracted business, EDS is currently a seven
billion dollar company growing revenues at an annual rate of 15 percent,
some three times as fast as the phone companies. EDS will add a billion
dollars or so in new sales in 1992 alone. If the company is to continue to
supply leading edge services to its customers, it must command leading edge
communications. To EDS, that means dumb and dark networks.
THE "DARK FIBER" CASE
That need has driven EDS into an active role as an ex parte pleader in
Federal Case 911416, currently bogging down in the District of Columbia
Federal Court of Appeals as the so-called "dark fiber" case. On the
surface, the case, known as Southwestern Bell et al versus the Federal
Communications Commission and the U.S. Justice Department, pits four
Regional Bell telephone companies against the FCC. But the legal maneuvers
actually reflect a rising conflict between the Bells and several large
corporate clients over the future of communications.
Beyond all the legal posturing, the question at issue is whether fiber
networks should be dumb and dark, and cheap, the way EDS and other
customers like them. Or whether they should be bright and smart, and
"strategically" priced, the way the telephone companies want them.
On the side of intelligence and light are the phone companies;
Southwestern Bell, U.S. West, Bell South, and Bell Atlantic. The forces of
darkness include key officials at the FCC and such companies as Shell Oil,
the information services arm of McDonald Douglas, long distance network
provider Wiltel, as well as EDS.
For most of the four year course of the struggle, it has passed
unnoticed by the media. In summary, the issue may not seem portentous.
The large corporate customers want dark fiber; the FCC mandates that it be
supplied; the Bells want out of the business. But for all their obscurity,
the proceedings raise what for the next twenty years will be the central
issue in communications law and technology. The issue, if not the possible
trial itself, will shape the future of both the computer and telephone
industries during a period when they are merging to form the spearhead of a
new information economy.
"Dark fiber" is simply a glass fiber optic thread with nothing
attached to it, (ie. no light being sent through it). In this "unlit"
condition, it is available for use without the intermediation of phone
company electronics or intelligent services.
In the mid-1980s, the Bells leased some of their dark fiber lines to
several large corporations on an individual case basis. These companies
learned to love dark fiber. But when they tried to renew their leases with
the Bells, the Bells clanged no! Why don't you leave the interconnections
and protocols to us? Why don't you use our marvellous smart network with
all the acronyms and intelligent services? Why don't you let us meter your
use of the fiber and send you a convenient monthly bill for each packet of
bits you send?
EDS and the other firms rejected the offer; they preferred that dumb
fiber to the intelligent network. When the Bells persisted in an effort to
deny new leases, the companies went to the FCC to require the Bells, as
regulated "common carrier" telephone companies, to continue supplying dark
fiber.
In the fall of 1990, the FCC ruled that the phone companies would have
to offer dark fiber to all comers under the rules of common carriage.
Rather than accept this new burden, the phone companies petitioned to
withdraw from the business entirely under what is called a rule 214
application. Since the FCC has not acted on this petition, the Bells are
preparing to go to court to force the issue. Their corporate customers are
ready to litigate as well.
It is safe to say that none of the participants fully comprehend the
significance of their courthouse confrontation. To the Bells, after all is
said and done, the key problem is probably the price. Under the existing
tariff, they are required to offer this service to anyone who wants it for
an average price of approximately $150 per strand of fiber per month. As
an offering that competes with their T-3 45 megabit (millions of bits) a
second lines and other forthcoming marvels, dark fiber threatens to gobble
up their future as vendors of broadband communications to offices, even as
cable TV preempts them as broadband providers to homes. Since the Bells'
profits on data are growing some 10 times as fast as their profits on voice
telephony, they see dark fiber as a menace to their most promising markets.
The technological portents, however, are far more significant even
than the legal and business issues. The coming triumph of dark fiber will
mean not only the end of the telephone industry as we know it but also the
end of the telephone industry as they plan it: a vast intelligent fabric
of sophisticated information services. It also could mean a thoroughgoing
restructuring of a computer industry increasingly dedicated to supplying
"smart networks." Indeed, for most of the world's communications companies,
professors of communications theory, and designers of new computer
networks, the triumph of dark and dumb means "back to the drawing board,"
if not back to the dark ages.
But the new dark ages cannot be held back.
Springing out the depths of IBM's huge Watson Laboratories is a
powerful new invention: the all optical network, that will soon relegate
all bright and smart executives to the Troglodyte file and make dumb and
dark the winning rule in communications.
THE WRINGER EFFECT
From time to time, the structure of nations and economies goes through
a technological wringer. A new invention radically reduces the price of a
key factor of production and precipitates an industrial revolution. Before
long, every competitive business in the economy must wring out the residue
of the old costs and customs from all its products and practices.
The steam engine, for example, drastically reduced the price of
physical force. Power once wreaked at great expense from human and animal
muscle pulsed cheaply and tirelessly from machines burning coal and oil.
Throughout the world, dominance inexorably shifted to businesses and
nations that reorganized themselves to exploit the suddenly cheap resource.
Eventually every human industry and activity, from agriculture and sea
transport to printing and war, had to centralize and capitalize itself to
take advantage of the new technology.
Putting the world through the technological wringer over the last
three decades has been the integrated circuit, the IC. Invented by Robert
Noyce of Intel and Jack Kilby of Texas Instruments in 1959, the IC put
entire systems of tiny transistor switches, capacitors, resistors, diodes,
and other once costly electronic devices on one tiny microchip. Made
chiefly of silicon, aluminum, and oxygen, three of the most common
substances on earth, the microchip eventually reduced the price of
electronic circuitry by a factor of a million.
As industry guru Andrew Rappaport has pointed out, electronic
designers now treat transistors as virtually free. Indeed, on memory
chips, they cost some 400 millionths of a cent. To waste time or battery
power or radio frequencies may be culpable acts, but to waste transistors
is the essence of thrift. Today you use millions of them slightly to
enhance your TV picture or to play a game of solitaire or to fax Doonsbury
to Grandma. If you do not use transistors in your cars, your offices, your
telephone systems, your design centers, your factories, your farm gear, or
your missiles, you go out of business. If you don't waste transistors,
your cost structure will cripple you. Your product will be either too
expensive, too slow, too late, or too low in quality.
Endowing every information age engineer or PC hacker with the creative
potential of a factory owner of the industrial age, the microchip reversed
the centralizing thrust of the previous era. All nations and businesses
had to adapt to the centrifugal law of the microcosm, flattening
hierarchies, outsourcing services, liberating engineers, shedding middle
management. If you did not adapt your business systems to the new regime,
you would no longer be a factor in the world balance of economic and
military power.
During the next decade or so, industry will go through a new
technology wringer and submit to a new law: the law of the telecosm. The
new wringer, the new integrated circuit, is called the all optical network.
It is a communications system that runs entirely in glass. Unlike existing
fiber optic networks, which convert light signals to electronic form in
order to amplify or switch them, the all optical network is entirely
photonic. From the first conversion of the signal from your phone or
computer to the final conversion to voice or data at the destination, your
message flies through glass on wings of light.
Just as the old integrated circuit put entire electronic systems on
single slivers of silicon, the new IC will put entire communications
systems on seamless webs of silica. Wrought in threads as thin as a human
hair, this silica is so pure that you could see through a window of it
seventy miles thick. But what makes the new wringer roll with all the
force of the microchip revolution before it is not the purity but the
price. Just as the old IC made transistor power virtually free, the new
IC, the all optical network, will make communications power virtually free.
Another word for communications power is bandwidth. Just as the
entire world had to learn to waste transistors, the entire world will now
have to learn how to waste bandwidth. In the 1990s and beyond, every
industry and economy will go through the wringer again.
The impact on the organization of companies and economies, however,
has yet to become clear. What is the law of the telecosm? Will the new
technology reverse the centrifugal force of the microchip revolution...or
consummate it? To understand the message of the new regime, we must follow
the rule of microcosmic prophet Carver Mead of Caltech: "Listen to the
technology...and find out what it is telling us."
THE SHANNON-SHOCKLEY REGIME
The father of the all-optical-network, the man who coined the phrase,
built the first fully functional system, and wrote the definitive book on
the subject, is Paul E. Green, Jr. of Watson Laboratory at IBM. Now
standing directly in the path of Green's wringer is Robert Lucky, who some
seven years ago at a conference at Cornell first gave Green the idea that
an all optical network might be possible.
The leading intellectual in telephony, Lucky recently shocked the
industry by shifting from AT&T's Bell Labs, where he was executive director
of research, to Bellcore, the laboratory of the Regional Bell Operating
Companies (RBOCs). There he will soon have to confront the implications of
Green's innovation.
Contemplating the new technology, Lucky recalls a course on data
networks that he used to teach many years ago with Green. As a computer
man, Green relished the contrast between the onrushing efficiencies in his
technology and the relative dormancy in communications. Indeed, for some
twenty five years, while computer powers rose a millionfold, network
capacities increased about a thousandfold. It was not until the late 1980s
that most long distance data networks much surpassed the Pentagon's
"ARPANET" running at 50 kilobits (thousands of bits) per second since the
mid sixties.
This was the era dominated by the powerful mathematic visions and
theories of Claude Shannon of MIT and Bell Labs. Shannon was the reclusive
genius who invented Information Theory to ascertain the absolute carrying
capacity of any communications channel.
Whether wire or air, channels were assumed to be narrow and noisy, the
way God made them (sometimes with help from AT&T). Typical were the copper
phone lines that still link every household to the telephone network and
the air waves that still bear radio and television signals and static.
The all-purpose remedy for these narrow, noisy channels was powerful
electronics. Invented at Bell Laboratories by a team headed by William
Shockley and then developed by Robert Noyce and other Shockley proteges in
Silicon Valley, silicon transistors and integrated circuits engendered a
constant exponential upsurge of computing power.
Throwing ever more millions of ever faster and cheaper transistors at
every problem, engineers created fast computers, multiplexors, and switches
that seemed to surmount and outsmart every limit of bandwidth or
restriction of wire. This process continues today with heroic new
compression tools that allow the creation of full video conferences over 64
kilobit telephone connections. Scientists at Bellcore are now even
proposing new ways of using the Motion Picture Engineering Group (MPEG)
compression standard to send full motion movies at 1.5 megabits a second
over the 4 kilohertz twisted pair copper wires to the home. Using ever
faster computers, the telephone company is saying it can give you pay-per-
view movies without installing fiber, or even coaxial cable, to the home.
In the Shannon-Shockley era, the communications might be noisy and
error prone, but smart electronics could encode and decode messages in
complex ways that allowed efficient identification and correction of all
errors. The Shannon channel might be narrow, but fast multiplexors allowed
it to be divided into time slots accommodating a large number of
simultaneous users in a system called time division multiplexing. The
channel might clog up when large numbers of users attempted to communicate
with each other at once, but collision detectors or token passers could
sort it all out in nanoseconds. Graphics and video might impose immense
floods of bits on the system, but compression technology could reduce the
floods to a manageable trickle with little or no loss of picture quality.
If all else failed, powerful electronic switches could compensate for
almost any bandwidth limitations. Switching could make up for the
inadequate bandwidth at the terminals by relieving the network of the need
to broadcast all signals to every destination. Instead, the central switch
could receive all signals and then route them to their appropriate
addresses.
To this day, this is the essential strategy of the telephone
companies: compensate for narrow noisy bandwidth with ever more powerful
and intelligent digital electronics. Their "core competence," the Bells
hasten to tell you, is switching. They make up for the shortcomings of
copper wires by providing smart, powerful digital switches.
Their vision for the future is to join the computer business all the
way, making these switches the entering wedge for ever more elaborate
information services. Switches will grow smarter and more sophisticated
until they provide an ever growing cornucopia of intelligent voice and fax
features, from caller ID and voice mail to personal communications systems
that follow you and your number around the world from your car commute to
your vacation beach hideaway. In the end, these intelligent networks could
supply virtually all the world's information needs, from movies, games and
traffic updates to data libraries, financial services, news programs, and
weather reports, all climaxing with yellow pages that exfoliate into a
gigantic global mall of full motion video where your fingers walk (or your
voice commands echo) from Harrods, to Jardines, to Akihabara, to Century 21
without you leaving the couch.
At the time when Green and Lucky taught their course, this strategy
for the future was only a glimmer in the minds of telephone visionaries.
But the essence of it was already in place. As Green pointed out,
telephone companies' response to sluggishness in communications was to
enter the computer industry, where progress was faster. The creativity of
digital electronics would save the telephone industry from technical
stagnation.
Lucky, however, protested to Green that it was unjust to compare the
two fields. Computers and telecom, as Lucky explained it, operate on
entirely different scales. Computers work in the microscale world of the
IC, putting ever more thousands of wires and switches on single slivers of
silicon.
By contrast, telecommunications functions in the macroworld, laying
out wires and switches across mostly silicon landscapes and seabeds. It
necessarily entails a continental, or even intercontinental stretch of
cables, microwave towers, switches, and poles. "How was it possible,"
Lucky asked, "to make such a large scale system inexpensive?" Inherent in
the structure and even the physics of computers and telecommunications, so
it seemed to Lucky two decades ago, was a communications bottleneck.
As Lucky remembers it, Green was never satisfied with Lucky's point.
Green believed that someday communications could achieve miracles
comparable to the integrated circuit in computing....
THE BANDWIDTH SCANDAL
Today, as Lucky was the first to announce, fiber optics has utterly
overthrown the previous relationship between fast computers and slow wires.
Now it is computer technology that imposes the bottleneck on the vast
vistas of dark fiber.
A silicon transistor can change its state some 2.5 billion times a
second in response to light pulses (bundles of photons) hitting a photo-
detector. Since it would take a human being a thousand years or so of 10
hour workdays even to count to two billion, two billion cycles in a single
second (two gigahertz) might seem a sprightly pace. But in the world of
fiber optics running at the speed and frequencies of light, even a rate of
two billion cycles a second is a humbling bow to the slothful pace of
electronics. Since optical signals still have to be routed to their
destinations through computer switches, communications now suffers from
what is known as the "electronic bottleneck."
It is this electronic bottleneck, the entire Bell edifice of Shannon
and Shockley, that Paul Green plans to blow away with his all optical
networks. Green is targeting what is a secret scandal of modern
telecommunications: the huge gap between the real capacity of fiber optics
and the actual speed of telephone communications.
In communications systems, the number of waves per second (or hertz)
represents a rough measure of its potential bandwidth or ultimate carrying
capacity. The bandwidth of a radio system, for example, is determined by
the frequency of each station or channel and by the number of stations that
can fit within the band. Your AM dial, for example, runs from around 535
thousand hertz (kilohertz) to 1705 kilohertz and each station uses some 10
kilohertz. With an ideal receiver, the AM passband might carry 117
stations.
By contrast, the intrinsic bandwidth of one strand of dark fiber is
some 25 thousand gigahertz in each of three groups of frequencies (three
passbands) through which fiber can transmit light over long distances. At
a gigahertz per terminal, this bandwidth might accommodate some 25,000
supercomputer "stations" (or 2.5 billion AM stations). Using what is
called dispersion shifted fiber, it may be possible to use two of these
passbands at once: a total of some 40 or 50 thousand gigahertz. For
comparison, consider all the radio frequencies currently used in the air
for radio, television, microwave, and satellite communications and multiply
by two thousand. The bandwidth of one fiber thread could carry more than
two thousand times as much information as all these radio and microwave
frequencies that currently comprise the "air." One fiber thread could bear
twice the traffic on the phone network during the peak hour of Mothers' Day
in the U.S. (the heaviest load currently managed by the phone system).
Yet even for point-to-point long distance links, let alone connections
to homes, telephone and computer network engineers now turn their backs on
this immense capacity and use perhaps one or two fifty thousandths it.
Deferring to the electronic bottleneck, the telephone industry uses fiber
merely as a superior replacement for the copper wires, coaxial cables,
satellite links, and microwave towers that connected the local central
office switches to one another for long distance calls.
Over the last 15 years, the Bell Laboratory record for fiber optics
communication has run from 10 megabits per second over a one kilometer span
to some 10 gigabits per second over nearly one thousand kilometers. But
all the heroic advances in point-to-point links between central offices
continued to use essentially one frequency on a fiber thread, while
ignoring its intrinsic power to accommodate thousands of useful
frequencies.
In a world of all optical networks, this strategy is bankrupt. No
longer will it be possible to throw more transistors, however cheap and
fast, at the switching problem. Electronic speeds have become an
insuperable bottleneck obstructing the vast vistas of dark fiber beyond.
So called gigabit networks planned by the telephone and computer
companies will not do. What is needed is not a gigabit spread among many
terminals, but a large network functioning at a gigabit per second per
terminal.
The demands of EDS offer a hint of the most urgent business needs.
Added to them will be consumer demands. True high definition television,
comparable to movies in resolution, requires close to gigabit-a-second
bandwidth, particularly if the program is dispatched to the viewer in burst
mode all at once in a few seconds down the fiber, or if the user is given a
chance to shape the picture, choose a vantage point, window several images
at once, or experience three dimensions. When true broadband channels
become available, there will be a flood of new applications comparable to
the thousands of new uses of the IC.
No foreseeable progress in electronics can overcome the electronic
bottleneck. To do that, we need an entirely new communications regime. In
the form of the all optical network, this regime is now at hand.
LAW OF THE TELECOSM: NETWORKS DUMB AS A STONE
The new regime will use fiber not as a replacement for copper wires
but as a new form of far more capacious and error-free air. Through a
system called wavelength division multiplexing and access, computers and
telephones will tune into desired messages in the fibersphere the same way
radios now tune into desired signals in the atmosphere. The fibersphere
will be intrinsically as dumb and dark as the atmosphere.
The new regime overcomes the electronic bottleneck by altogether
banishing electronics from the network. But, ask the telcos in unison,
what about the switches? As long as the network is switched, it must be
partly electronic. Unless the network is switched, it is not a true any-
to-any network. It is a broadcast system. It may offer a cornucopia of
services. But it cannot serve as a common carrier like the phone network
allowing any party to reach any other. Without intelligent switching it
cannot provide personal communications nets that can follow you wherever
you go. Without intelligent switching, the all optical network, so they
say, is just a glorified cable system.
These critics fail to grasp a central rule of the telecosm: bandwidth
is a nearly perfect substitute for switching. With sufficient physical
bandwidth, it is possible to simulate any kind of logical switch
whatsoever. Bandwidth allows creation of virtual switches that to the user
seem to function exactly the way physical switches do. You can send all
messages everywhere in the network, include all needed codes and
instructions for correcting, decrypting, and reading them, and allow each
terminal to tune into its own messages on its own wavelength, just like a
two-way radio. When the terminals are smart enough and the bandwidth great
enough, your all optical network can be as dumb as a stone.
Over the last several years, all optical network experiments have been
conducted around the world, from Bellcore in New Jersey to NTT at Yokosuka,
Japan. British Telecom has used wavelength division multiplexing to link
four telephone central offices in London. Columbia's Telecom Center has
launched a "Teranet" that lacks tunable lasers or receivers but can
logically simulate them. Bell Laboratories has generated most of the
technology but as a long distance specialist has focussed on the project of
sending gigabits of information thousands of miles without amplifiers. But
only fully functional system is the Rainbow created by Paul Green at IBM.
As happens so often in this a world of technical disciplines sliced
into arbitrary fortes and fields, the large advances come from the
integrators. Paul Green is neither a laser physicist, nor an optical
engineer, nor a telecommunications theorist. At IBM, his work has ranged
from overseeing speech recognition projects at Watson Labs to shaping
company strategy at corporate headquarters in Armonk. His most recent
success was supervising development of the new APPN (Advanced Peer to Peer
Network) protocol. According to an IBM announcement in March, APPN will
replace the venerable SNA (systems network architecture) that has been
synonymous with IBM networking for more than a decade.
Green took some pride in this announcement, but by that time, the
project was long in his past. He was finishing the copy editing on his
magisterial tome on Fiber Optic Networks (published this summer by Prentice
Hall). And he was moving on to more advanced versions of the Rainbow which
he and his team had introduced in December 1991 at the Telecom 91
Conference in Geneva and which has been installed between the various
branches of Watson Laboratories in Westchester County, N.Y.
As Peter Drucker points out, a new technology cannot displace an old
one unless it is proven at least 10 times better. Otherwise the billions
of dollars worth of installed base and thousands of engineers committed to
improving the old technology will suffice to block the new one. The job of
Paul Green's 15 man team at IBM is to meet that tenfold test.
Green's all optical network creates a fibersphere as neutral and
passive as the atmosphere. It can be addressed by computers the same way
radios and television sets connect to the air. Consisting entirely of
unpowered glass and passive spitters and couplers, the fibersphere is dark
and dumb. Any variety of terminals can interconnect across it at the same
time using any protocols they choose.
Just as radios in the atmosphere, computer receivers connected to the
fibersphere do not find a series of bits in a message; they tune into a
wavelength or frequency. Because available Fabry Perot tunable filters
today have larger bandwidth than tunable lasers, Green chose to locate
Rainbow's tuning at the receiver and have transmitters each operate at a
fixed wavelength. But future networks can use any combination of tunable
equipment at either end.
When Green began the project in 1987, the industry stood in the same
general position as the pioneers of radio in the early years of that
industry. They had seemingly unlimited bandwidth before them, but lacked
transmitters and receivers powerful enough to use it effectively. Radio
transmitters suffered "splitting losses" as they broadcast their signals
across the countryside. Green's optical messages lose power everytime they
are split off to be sent to another terminal or are tapped by a receiver.
The radio industry solved this problem by the development of the
audion triode amplifier. Green needed an all optical amplifier to replace
the optoelectronic repeaters that now constitute the most widespread
electronic bottleneck in fiber. Amplifiers in current fiber networks first
convert the optical signal to an electronic signal, enhance it, and then
convert it back to photons.
Like the pioneers of radio, Green soon had his amplifier in hand.
Following concepts pioneered by David Payne at the University of
Southhampton in England, a Bell Laboratories group led by Emmanuel
Desurvire and Randy Giles developed a workable all optical device. They
showed that a short stretch of fiber doped with erbium, a rare earth
mineral, and excited by a cheap laser diode, can function as a powerful
amplifier over the entire wavelength range of a 25,000 gigahertz system.
Today such photonic amplifiers enhance signals in a working system of links
between Naples and Pomezia on the west coast of Italy. Manufactured in
packages between two and three cubic inches in size, these amplifiers fit
anywhere in an optical network for enhancing signals without electronics.
This invention overcame the most fundamental disadvantage of optical
networks compared to electronic networks. You can tap into an electronic
network as often as desired without weakening the voltage signal. Although
resistance and capacitance will weaken the current, there are no splitting
losses in a voltage divider. Photonic signals, by contrast, suffer
splitting losses every time they are tapped; they lose photons until
eventually there are none left. The cheap and compact all optical
amplifier solves this problem.
Not only did Green and his IBM colleagues create working all optical
networks, they also reduced the interface optoelectronics to a single
microchannel plug-in card that can fit in any IBM PS/2 level personal
computer or R6000 workstation. Using off-the-shelf components costing a
total of $16,000 per station, Rainbow achieved a capacity more than 90
times greater than FDDI at an initial cost merely four times as much.
Just as Jack Kilby's first ICs were not better than previous adders
and oscillators, the Rainbow I is not better in some respects than rival
networks based on electronics. At present it connects only 32 computers at
a speed of some 300 megabits per second, for a total bandwidth of 9.5
gigabits. This rate is huge compared to most other networks, but it is
still well below the target of a system that provides gigabit rates for
every terminal.
A more serious limitation is the lack of packet switching. Rather
than communicating down a dedicated connection between two parties, like
phones do, computer networks send data in small batches, called packets,
each bearing its own address. This requires switching back and forth
between packets millions of times a second. Neither the current Rainbow's
lasers nor its filters can tune from one message to another more than
thousands of times a second. This limitation is a serious problem for
links to mainframes and supercomputers that may do many tasks at once in
different windows on the screen and with connections to several other
machines.
As Green shows, however, all these problems are well on the way to
solution. A tide of new interest in all optical systems is sweeping
through the world's optical laboratories. The Pentagon's Defense Advanced
Projects Agency (DARPA) has launched a program for all optical networking.
With Green installed as the new President of the IEEE Communications
Society, the technical journals are full of articles on new wavelength
division technology. Every few months brings new reports of a faster laser
with a broader bandwidth, or filter with faster tuning, or an ingenious new
way to use bandwidth to simulate packet switching. Today lasers and
receivers can switch fast enough but they still lack the ability to cover
the entire bandwidth needed.
The key point, however, is that as demonstrated both in Geneva and
Armonk, the Green system showed the potential efficiency of all optical
systems. Even in their initial forms they are more cost effective in
bandwidth per dollar than any other network technology. Scheduled for
introduction within the next two years, Rainbow III will comprise a
thousand stations operating at a gigabit a second, with the increasingly
likely hope of fast packet switching capability. At that point, the system
will be a compelling commercial product at least hundreds of times more
cost effective than the competition.
Without access to dark fiber, however, these networks will be
worthless. If the telephone companies fail to supply it, they risk losing
most of the fastest growing parts of their business: the data traffic
which already contributes some 50 percent of their profits. But there is
also a possibility that they will lose much of their potential consumer
business as well: the planned profits in pay-per-view films and electronic
yellow pages. This is the message of a second great prophet of dark fiber,
Will Hicks of Southbridge, Massachusetts.
A venerable inventor of scores of optical products, Hicks believes
that Green's view of the future of fiber is too limited. Using wavelength
division, Hicks can see the way to deliver some 500 megahertz two-way
connections to all the homes in America for some $400 per home. That is
fifty times the 10 megahertz total capacity of an Ethernet (with no one
else using it) for some 20 percent of the cost. That is capacity in each
home for twenty digital two-way HDTV channels at once at perhaps half the
cost of new telephone connections. Then, after a large consumer market
emerges for fiber optics, Hicks believes, Green's sophisticated computer
services will follow as a matter of course.
The consumer market, Hicks maintains, is the key to lowering the cost
of the components to a level where they can be widely used in office
networks as well. He cites the example of the compact disk laser diode.
Once lasers were large and complex devices, chilled with liquid nitrogen,
and costing thousands of dollars; now they are as small as a grain of salt,
cheap as a box of cereal, and more numerous than phonograph needles. An
executive at Hitachi told Hicks that Hitachi could work a similar
transformation on laser diodes and amplifiers for all optical networks.
"Just tell me what price you want to pay and I'll tell you how many you
have to buy."
The divergence of views between the IBM executive and the wildcat
inventor, however, is far less significant than their common vision of dark
fiber as the future of communications. By the power of ever cheaper
bandwidth, it will transform all industries of the coming information age
just as radically as the power of cheaper transistors transformed the
industries of the computer age.
For the telephone companies, the age of ever smarter terminals
mandates the emergence of ever dumber networks. This is a major strategic
challenge; it takes a smart man to build a dumb network. But the telcos
have the best laboratories and have already developed nearly all the
components of the fibersphere.
Telephone companies may complain of the large costs of the
transformation of their system, but they command capital budgets as large
as the total revenues of the cable industry. Telcos may recoil in horror
at the idea of dark fiber, but they command webs of the stuff ten times
larger than any other industry. Dumb and dark networks may not fit the
phone company self-image or advertising posture. But they promise larger
markets than the current phone company plan to choke off their future in
the labyrinthine nets of an "intelligent switching fabric" always behind
schedule and full of software bugs.
The telephone companies cannot expect to impose a uniform network
governed by universal protocols. The proliferation of digital protocols
and interfaces is an inevitable effect of the promethean creativity of the
computer industry. Green explains, "You cannot fix the protocol zoo. You
must use bandwidth to accommodate the zoo."
As Robert Pokress, a former switch designer at Bell Labs now head of
Unifi Corporation, points out, telephone switches (now 80 percent software)
are already too complex to keep pace with the efflorescence of relatively
simple computer technology on their periphery. While computers become ever
more lean and mean, turning to reduced instruction set processors, networks
need to adopt reduced instruction set architectures. The ultimate in dumb
and dark is the fibersphere now incubating in their magnificent
laboratories.
The entrepreneurial folk in the computer industry may view this
wrenching phone company adjustment with some satisfaction. But the fact is
that computer companies face a strategic reorientation as radical as the
telcos do. In a world where ever smarter terminals require ever dumber
communications, computer networks are as gorged and glutted with smarts as
phone company networks and even less capacious. The nation's most
brilliant nerds, commanding the 200 MIPS Silicon Graphics superstations or
Mac Quadra multimedia power plants, humbly kneel before the 50 kilobit
lines of the Internet and beseech the telcos to upgrade to 64 kilobit basic
ISDN.
Now addicted to the use of transistors to solve the problems of
limited bandwidth, the computer industry must use transistors to exploit
the opportunities of nearly unlimited bandwidth. When home-based machines
are optimized for manipulating high resolution digital video at high
speeds, they will necessarily command what are now called supercomputer
powers. This will mean that the dominant computer technology will emerge
first not in the office market but in the consumer market. The major
challenge for the computer industry is to change its focus from a few
hundred million offices already full of computer technology to a billion
living rooms now nearly devoid of it.
Cable companies possess the advantage of already owning dumb networks
based on the essentials of the all optical model of broadcast and select--
of customers seeking wavelengths or frequencies rather than switching
circuits. Cable companies already provide all the programs to all the
terminals and allow them to tune in to the desired messages. Uniquely in
the world, U.S. cable firms already offer a broadband pipe to ninety
percent of American homes. These coaxial cables, operating at one
gigahertz for several hundred feet, provide the basis for two way broadband
services today. But the cable industry cannot become a full service
supplier of telecommunications until it changes its self-image from a cheap
provider of one way entertainment services into a common carrier of two way
information. Above all, the cable industry cannot succeed in the digital
age if it continues to regard the personal computer as an alien and
irrelevant machine.
Analogous to the integrated circuit in its economic power, the all
optical network is analogous to the massively parallel computer in its
technical paradigm. In the late 1980s in computers, the effort to make one
processor function ever faster on a serial stream of data reached a point
of diminishing returns. Superpipelining and superscalar gains hit their
limits. Despite experiments with Josephson Junctions, high electron
mobility, and cryogenics, usable transistors simply could not made to
switch much faster than a few gigahertz.
Computer architects responded by creating machines with multiple
processors operating in parallel on multiple streams of data. While each
processor worked more slowly than the fastest serial processors, thousands
of slow processors in parallel could far outperform the fastest serial
machines. Measured by cost effectiveness, the massively parallel machines
dwarfed the performance of conventional supercomputers.
The same pattern arose in communications and for many of the same
reasons. In the early 1990s the effort to increase the number of bits that
could be time division multiplexed down a fiber on a single frequency band
had reached a point of diminishing returns. Again the switching speed of
transistors was the show stopper. The architects of all optical networks
responded by creating systems which can use not one wavelength or frequency
but potentially thousands in parallel.
Again, the new systems could not outperform time division multiplexing
on one frequency. But all optical networks opened up a vast vista of some
75 thousand gigahertz of frequencies potentially usable for communications.
That immense potential of massively parallel frequencies left all methods
of putting more bits on a single set of frequencies look as promising as
launching computers into the chill of outer space in order to accelerate
their switching speeds.
Just as the law of the microcosm made all terminals smart,
distributing intelligence from the center to the edges of the network, so
the law of the telecosm creates a network dumb enough to accommodate the
incredible onrush of intelligence on its periphery. Indeed, with the one
chip supercomputer on the way, manufacturable for under a hundred dollars
toward the end of the decade, the law of the microcosm is still gaining
momentum. The fibersphere complements the promise of ubiquitous computer
power with equally ubiquitous communications.
What happens, however, when not only transistors but also wires are
nearly free? As Robert Lucky observes in his forward to Paul Green's book,
"Many of us have been conditioned to think that transmission is inherently
expensive; that we should use switching and processing wherever possible to
minimize transmission." This is the law of the microcosm. But as Lucky
speculates, "The limitless bandwidth of fiber optics changes these
assumptions. Perhaps we should transmit signals thousands of miles to
avoid even the simplest processing function." This is the law of the
telecosm: use bandwidth to simplify everything else.
Daniel Hillis of Thinking Machines Corporation offers a similar
vision, adding to Lucky's insight the further assertion that massively
parallel computer architectures are so efficient that they can overthrow
the personal computer revolution. Hillis envisages a powerplant computer
model, with huge Thinking Machines at the center tapped by millions of
relatively dumb terminals.
All these speculations assume that the Law of the Telecosm usurps the
Law of the Microcosm. But in fact the two concepts function in different
ways in different domains.
Electronic transistors use electrons to control, amplify, or switch
electrons. But photonics differ radically from electronics. Because
moving photons do not affect one another on contact, they cannot readily be
used to control, amplify, or switch each other. Compared to electrons,
moreover, photons are huge: infrared photons at 1550 or 1300 nanometers
are larger than a micron across. They resist the miniaturization of the
microcosm. For computing, photons are far inferior to electrons. With
single electron electronics now in view, electrons will keep their
advantage. For the foreseeable future, computers will be made with
electrons.
What are crippling flaws for photonic computing, however, are huge
assets for communicating. Because moving photons do not collide with each
other or respond to electronic charges, they are inherently a two way
medium. They are immune to lightning strikes, electromagnetic pulses, or
electrical power surges that destroy electronic equipment. Virtually
noiseless and massless pulses of radiation, they move as fast and silently
as light.
Listening to the technology, as Caltech prophet Carver Mead
recommends, one sees a natural division of labor between photonics and
electronics. Photonics will dominate communications and electronics will
dominate computing. The two technologies do not compete; they are
beautiful complements of each other.
The law of the microcosm makes distributed computers (smart terminals)
more efficient regardless of the cost of linking them together. The law of
the telecosm makes dumb and dark networks more efficient regardless of how
numerous and smart are the terminals. Working together, however, these two
laws of wires and switches impel ever more widely distributed information
systems.
It is the narrow bandwidth of current phone company connections that
explains the persistence of centralized computing in a world of distributed
machines. Narrowband connections require smart interfaces and complex
protocols and expensive data. Thus you get your online information from
only a few databases set up to accommodate queries over the phone lines.
You limit television broadcasting to a few local stations. Using the
relatively narrowband phone network or television system, it pays to
concentrate memory and processing at one point and tap into the hub from
thousands of remote locations.
Using a broadband fiber system, by contrast, it will pay to distribute
memory and services to all points on the network. Broadband links will
foster specialization. If the costs of communications are low, databases,
libraries, and information services can specialize and be readily reached
by customers from anywhere. On line services lose the economies of scale
that lead a firm such as Dialog to attempt to concentrate most of the
world's information in one set of giant archives.
By making bandwidth nearly free, the new integrated circuit of the
fibersphere will radically change the environment of all information
industries and technologies. In all eras, companies tend to prevail by
maximizing the use of the cheapest resources. In the age of the
fibersphere, they will use the huge intrinsic bandwidth of fiber, all 25
thousand gigahertz or more, to replace nearly all the hundreds of billions
of dollars worth of switches, bridges, routers, converters, codecs,
compressors, error correctors, and other devices, together with the
trillions of lines of software code, that pervade the intelligent switching
fabric of both telephone and computer networks.
The makers of all this equipment will resist mightily. But there is
no chance that the old regime can prevail by fighting cheap and simple
optics with costly and complex electronics and software.
The all optical network will triumph for the same reason that the
integrated circuit triumphed: it is incomparably cheaper than the
competition. Today, measured by the admittedly rough metric of MIPS per
dollar, a personal computer is more than one thousand times more cost
effective than a mainframe. Within 10 years, the all optical network will
be millions of times more cost effective than electronic networks. Just as
the electron rules in computers, the photon will rule the waves of
communication.
The all optical ideal will not immediately usurp other technologies.
Vacuum tubes reached their highest sales in the late 1970s. But just as
the IC inexorably exerted its influence on all industries, the all optical
technology will impart constant pressure on all other communications
systems. Every competing system will have to adapt to its cost structure.
In the end, almost all electronic communications will go through the
wringer and emerge in glass.
This is the real portent of the dark fiber case wending its way
through the courts. The future of the information age depends on the rise
of dumb and dark networks to accommodate the onrush of ever smarter
electronics. Ultimately at stake is nothing less than the future of the
computer and communications infrastructure of the U.S. economy, its
competitiveness in world markets, and the consummation of the age of
information. Although the phone companies do not want to believe it, their
future will be dark.
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~ 1st 1.10b #1477 ~
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Channel 1 (R) Cambridge, MA